Quantities of these N.O.S. carbon composition resistors are limited; most production has ceased in the USA. 'Carbon comps; remain popular with D.I.Y tube guitar and hi-fi amp builders; there's a rosy glow around the notes. Most of the vintage tube gear we know and love was built using this type of 'antique' carbon resistor; you'll see loads of old Stackpole and Allen-Bradley resistors in vintage Fenders, Marantz, etc. Allen-Bradley is considered by some to be the best example of this type of resistor with Stackpole and IRC close behind, but even the "maker uncertain" carbon comps we sell are equal in quality to those found in most classic tube gear. True, there is some thermal drift and a very slight bit of noise inherent in the design of carbon composition resistors but this is largely a 'non-issue' in most guitar amps circuits and most vintage hi-fi as well. Caveats? I wouldn't use carbon comps in a new microphone preamp design, a high gain phono preamp for low output moving coil phono cartridges or a headphone amp.